The dogs went on, but the horse boggled at the sudden appearance of the strange beast.

The horror of the deed and its consequences boggle the imagination.

Do by thy soul, when thou findest it shy of such meditations, as wee do by our horses, that are given to boggle and start when wee ride them; When they fly back, and start at anything in the way, we do not yield to their fear, and go back (that will make them worse another time) but wee ride them up close to that they are afraid of, and so in time break them of that illquality. [1]

[…] we start and boggle at what is unusual: and like the Fox in the fable at his first view of the Lyon, we cannot endure the sight of the Bug-bear, Novelty.

1685, Isaac Barrow, Of Contentment, Patience and Resignation to the Will of God. Several Sermons, London: Brabazon Aylmer, Sermon 4, pp. 127-128,[3]

They are best qualified to thrive in [this world] […] whose designs all tend to their own private advantage, without any regard to the publick, or to the good of others; who can use any means conducible to such designs, bogling at nothing which serveth their purpose […]

From the tenour of your last letter however, I am led to imagine, that you have formed some new attachment.—If it be so, let me earnestly request you to see me once more, and immediately. This is the only proof I require of the friendship you profess for me. I will then decide, since you boggle about a mere form.

I would be loth to exchange consciences with them, and boggle so with God Almighty; but these men by a new kind of Metaphysick have found out a way to abstract the Person of the King from his Office to make his Soveraigntie a kinde of Platonick Idea hovering in the aire, while they visibly attempt to assail and destroy his person […]

^ "Knowledge and practice: or, A plain discourse of the chief things necessary to be known, believ'd, and practised in order to salvation ... The 2d edition revised and inlarged [1] 1665 publisher=William Grantham, Henry Mortlock, and William Miller